1. Field of Invention
This invention relates in general to the field of power integrity and more specifically to a method and apparatus to provide transient surge protection and continuous ground status monitoring for use with a watt-hour meter.
2. Background of the Invention
Electrical power is supplied to an individual site or service location by external electrical power line conductors provided by the electric utility companies. Typically, incoming power lines are connected to contacts residing within an electrical meter socket mounted on the wall of a building. Electrical load conductors used to supply electricity to the outlets within the site are connected to an additional set of contacts residing within the meter socket. A watt-hour meter is connected into the contacts in the meter socket to measure the electric use of the site.
Transient voltage conditions are known to exist on incoming power lines. The transient voltage conditions can be inherent to the incoming power lines or may be the result of a lightning strike. Surges, or brief pulses of high voltage, can destroy electronic circuitry and cause fire damage. Surge protection devices are well known in the art to provide safeguards against potentially dangerous electrical shock and destructive fire hazards. Additionally, it is known in the art to provide surge protection and transient voltage protection at a watt-hour meter. Watt-hour meter surge protection devices are known in the art to be integrated into the watt-hour meter through the use of meter socket extensions.
In addition to providing adequate surge protection, another important aspect of any electrical system is the establishment of a quality grounding system. The quality of the earth ground is dependent upon soil conditions, including base material, moisture content, the presence of salts and the number, depth and diameter of the grounding rods and their interconnections. A good ground can degrade to become a poor ground due to drought, freezing, erosion of conductive salts and corroded mechanical connections. While a good, quality ground may have been established when an electrical meter was originally installed, changing conditions in the soil and additional factors may result in a poor grounding condition that goes undetected.
In establishing a quality grounding system, consideration must be given to ground conductor resistance, ground current that may be present due to leakage current and ground voltage which is effected by stray voltage conditions.
The establishment and maintenance of a quality grounding system requires continuous monitoring of the ground conductor resistance, ground current and ground voltage.
Consequently, there is a need in the art for a method and device to provide continuous power line surge protection and ground conductor resistance, voltage and current monitoring for use with a watt-hour meter.
It is, therefore, to the effective resolution of the aforementioned problems and shortcomings of the prior art that the present invention is directed.
However, in view of the prior art in at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how the identified needs could be fulfilled.